1. Field of the Invention
This invention relates generally to communication systems and more specifically to wireless underwater communication systems utilizing the water as a conductor for the propagation of electromagnetic energy.
2. Description of the Prior Art
Until now, underwater communication and data transmission systems have been one of three major types.
The first type of communication system includes a metal wire electrical connector extending between a transmission unit and a reception unit. A problem with this "hard wired" system is that the rigors of underwater environments are such that the electrical connector will frequently break, especially when extended to great depths or over long distances.
Accoustic transmission such as "sonar" is also used for underwater communication for distances up to about 1,000 feet. A problem with accoustic transmission is that the intelligibility of the transmissions is often low due to the ambient noises, reverberations and thermocline echoes generated by underwater environments.
The third type of system utilizes the body of water as a conductor for electric field transmission. This system is an improvement over hard wired and accoustic transmission systems because it is relatively immune to the stresses and noises of underwater environment. However, a problem with the electric field transmission systems found in the prior art is that their transmission ranges are limited by the substantial electromagnetic radiation attenuation of natural bodies of water.